JP4564349B2 - Atomic layer deposition system - Google Patents

Description

  The present invention relates to an atomic layer deposition apparatus capable of forming a thin film in units of atomic layers and molecular layers.

  In recent years, an atomic layer deposition (ALD) method has been used as a technique for forming a uniform thin film on a large-area substrate with a fine lineability (see Patent Documents 1, 2, 3, and 4). The atomic layer growth method is a technique for forming a thin film in units of atomic layers by alternately supplying a raw material of each element constituting a film to be formed to a substrate. In the atomic layer growth method, only one layer or n layer is adsorbed on the surface while the raw materials for each element are being supplied, so that excess raw materials do not contribute to the growth. This is called self-stopping action of growth. Since the atomic layer growth method does not use plasma, a high-quality film can be formed. In addition, the atomic layer growth method has a feature that the application range is wide, for example, it is not necessary to increase the processing temperature to about 300 ° C. and an insulating film can be formed on a glass substrate.

  As shown in FIG. 4, a film forming apparatus for realizing an atomic layer growth method having such a feature includes a film forming chamber 401 in which a film is grown in a gas phase, and a film forming chamber 401 inside. And a substrate table 402 provided with a heating mechanism. The film formation chamber 401 includes an exhaust mechanism 404 and a gas supply mechanism 405. In the processing apparatus shown in FIG. 4, first, the substrate 403 to be processed is loaded onto the substrate table 402, the film formation chamber 401 is sealed, and then the substrate 403 is heated to a predetermined temperature by the heating mechanism of the substrate table 402. In the heated state, a predetermined gas supply by the gas supply mechanism 405, an exhaust by the exhaust mechanism 404, a purge by a purge gas supply by the gas supply mechanism 405, and an exhaust by the exhaust mechanism 404 are repeated. A thin film is formed.

The applicant has not yet found prior art documents related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in this specification.
JP-A-1-179423 JP-A-5-160152 JP 2001-172767 A JP 2002-353154 A

  By the way, from the viewpoint of reducing the manufacturing cost, the volume of the film forming chamber 401 is made as small as possible within a range that can accommodate the substrate to be processed. Therefore, it is difficult to use a large-diameter pipe in the exhaust path, and it has been difficult to increase the exhaust speed in the conventional film forming apparatus. For this reason, it takes time to exchange the source gas including the purge, and it is not easy to improve the film formation rate.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the deposition rate by shortening the exhaust time.

An atomic layer deposition apparatus according to the present invention includes a vacuum chamber having a sealable internal space, a deposition unit disposed in the vacuum chamber and having an opening, and a first region in a first region of the vacuum chamber. A first exhaust mechanism communicating with the pipe, a second exhaust mechanism communicating with the second area of the vacuum chamber via a second pipe having a larger diameter than the first pipe, and a predetermined gas inside the vacuum chamber. At least a gas supply mechanism for supplying, and the second region is outside the film forming chamber sealed by the film forming unit and the portion of the first region of the vacuum chamber, and is inside the vacuum chamber. The film forming chamber is pressed against the inner wall of the vacuum chamber with a predetermined pressing force so that the opening includes the first region, and the film forming chamber is sealed by the film forming unit and the first region of the vacuum chamber. Formed and gas supply Structure is obtained so as to supply the gas into the deposition chamber through a first region of the vacuum chamber. Therefore, when the internal pressure of the film forming chamber becomes larger than the pressure in the vacuum chamber beyond the pressing force, the film forming chamber is in communication with the inside of the vacuum chamber outside the film forming portion.

  In the atomic layer deposition apparatus, the vacuum chamber includes a flat top lid and an elastic member that supports the deposition unit to be pressed against the top lid inside the vacuum chamber, and the first region is disposed on the top lid. The film forming unit may be pressed against the inner wall of the upper lid by the elastic force of the elastic member. The first region may be disposed on the bottom surface of the vacuum chamber, and the film forming unit may be pressed against the bottom surface of the vacuum chamber by the weight of the film forming unit so that the opening includes the first region.

  As described above, in the present invention, a film forming chamber that is provided inside the vacuum chamber and has a different space inside the vacuum chamber is formed by the film forming unit whose opening is pressed against the inner wall. Therefore, by making the internal pressure of the film forming chamber larger than the pressure in the vacuum chamber more than the magnitude of the pressing force, the film forming chamber is brought into communication with the inside of the vacuum chamber outside the film forming unit, and film forming is performed. The chamber can be evacuated by the second exhaust mechanism through the second pipe having a larger diameter. As a result, according to the present invention, the exhaust time can be shortened, and the excellent effect that the film can be formed at a higher speed in the atomic layer growth method can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram including a schematic cross section schematically showing a configuration example of an atomic layer deposition apparatus according to an embodiment of the present invention. The apparatus shown in FIG. 1 includes a film forming unit 102 inside a vacuum chamber 101. In the vacuum chamber 101, for example, an exhaust mechanism 104 communicates with a bottom surface side via a pipe 103. The upper surface of the vacuum chamber 101 is composed of an openable / closable upper lid 105.

  The film forming unit 102 is a container having an open top surface, and the bottom surface side is supported on the bottom surface of the vacuum chamber 101 by a support unit 107 via an elastic member 106. The elastic member 106 may be made of, for example, a spring or rubber. In addition, a gas supply mechanism 108 for supplying a gas such as a source gas or a purge gas is connected to the region of the film formation unit 102 of the upper lid 105, and a film formation chamber exhaust mechanism 110 is connected via a pipe 109. Note that a substrate platform 121 having a heating mechanism is disposed at the bottom of the film forming unit 102.

  The film forming unit 102 is pushed up in the direction of the upper lid 105 by the elastic force (pressing force) of the elastic member 106, and the opened upper surface is pressed against the inner plane of the upper lid 105 to form a film forming chamber consisting of a sealed space inside. is doing. Therefore, when a force larger than the force pushing up the elastic member 106 is applied in the opposite direction, the upper surface of the film forming unit 102 is separated from the upper lid 105 as shown in FIG. As a result, the film formation chamber is partially opened inside the vacuum chamber 101. Note that the film forming unit 102 may be supported only by the elastic member 106 without using the support unit 107.

  Next, an example of an atomic layer deposition method using the atomic layer deposition apparatus shown in FIGS. First, it is assumed that the substrate to be processed is placed on the substrate platform 121 with the upper lid 105 opened. Next, the upper lid 105 is closed to bring the vacuum chamber 101 into a sealed state, and the film forming chamber exhaust mechanism 110 is operated to bring the inside of the film forming unit 102 to a pressure of about 2 to 3 Pa. Further, the exhaust mechanism 104 is operated so that the vacuum chamber 101 is also set to a pressure of about 2 to 3 Pa. Next, the temperature of the substrate is heated to about 300 ° C. by the heating mechanism provided in the substrate mounting table 121. This is the state shown in FIG.

Next, the gas supply mechanism 108 introduces, for example, SiCl ₄ gas as a source gas (adsorption gas) into the film forming unit 102 so that the source gas is supplied onto the substrate, and one layer is formed on the substrate. In this state, SiCl ₄ molecules are adsorbed. For example, the source gas may be supplied together with an inert carrier gas such as argon. By supplying the source gas, the pressure inside the film forming unit 102 is about 100 Pa. The source gas is supplied for about 1 to 2 seconds.

  Next, with the supply of the source gas stopped and the exhaust mechanism 104 and the film formation chamber exhaust mechanism 110 operated, a purge gas such as Ar or nitrogen is supplied into the film formation unit 102 by the gas supply mechanism 108. State. At this time, the purge gas is supplied to such an extent that the internal pressure of the film forming unit 102 is about 17000 Pa, for example. As a result, a large pressure difference is generated between the inside of the film forming unit 102 and the inside of the external vacuum chamber 101, and the pressure inside the film forming unit 102 becomes larger than the external pressure.

  Since this pressure difference is larger than the force by which the film forming unit 102 is pressed against the upper lid 105 by the elastic force of the elastic member 106, the film forming unit 102 is separated from the upper lid 105 as shown in FIG. The interior of 102 is in communication with the interior of the vacuum chamber 101. As a result, the inside of the film forming unit 102 is exhausted by the exhaust mechanism 104 and the film forming chamber exhaust mechanism 110 together with the inside of the vacuum chamber 101. Due to the communication, the pressure inside the film forming unit 102 is reduced to about 600 Pa.

  As a result, the replacement of the source gas with the purge gas inside the film forming chamber 102 (purge) is performed much faster than when the film forming chamber exhaust mechanism 110 is exhausted alone. In addition, unlike the inside of the film formation unit 102, the vacuum chamber 101 does not need to be made very small, and the pipe 103 can have a larger diameter than the pipe 109. In comparison, exhaust by the exhaust mechanism 104 can be performed at a higher speed. Therefore, as compared with the exhaust using only the film forming chamber exhaust mechanism 110, the exhaust using the exhaust mechanism 104 can perform a faster purge. For example, when only the film forming chamber exhaust mechanism 110 is evacuated, the purge requires 4 seconds or more. However, in the state shown in FIG. 2, the purge can be completed in about 1.5 seconds.

  By purging as described above, the surplus gas other than that adsorbed on the substrate is removed from the inside of the film forming unit 102. Subsequently, by introducing the oxidizing gas into the film forming unit 102 by the gas supply mechanism 108, the oxidizing gas is supplied onto the substrate, and the molecules adsorbed on the surface of the substrate react with the oxidizing gas, A silicon oxide thin film corresponding to one atomic layer of silicon is formed on the surface of the substrate. Thereafter, in the same manner as described above, the inside of the film forming unit 102 is purged with an inert gas such as Ar, so that excess gas is removed from the reaction chamber. The above-described source gas supply → purge → oxidation gas supply → purge is set as one cycle, and by repeating about 20 cycles, a silicon oxide thin film having a thickness of about 2 nm can be formed.

  When repeating 20 cycles in this way, purging is performed 39 times. Since there is a difference of 2.5 seconds in the time required for one purge between when exhausted by both the exhaust mechanism 104 and the film formation chamber exhaust mechanism 110, in the above case, when forming a 2 nm silicon oxide film In addition, 2.5 × 39 = 97.5 seconds can be shortened. Note that the force that presses the opening of the film forming unit 102 against the upper lid 105 is made by the elastic force of the elastic member 106, so the elastic force of the elastic member 106 depends on the weight of the film forming unit 102 and the purge gas supply conditions during the purge. May be set as appropriate.

  Next, another atomic layer deposition apparatus in the embodiment of the present invention will be described. FIG. 3 is a configuration diagram including a schematic cross section schematically showing a configuration example of another atomic layer deposition apparatus in the embodiment of the present invention. The apparatus shown in FIG. 3 includes a film forming unit 302 inside a vacuum chamber 301. In the vacuum chamber 301, for example, an exhaust mechanism 304 communicates with the upper surface side via a pipe 303. The film forming unit 302 is a container whose bottom side is open. In addition, a gas supply mechanism 308 for supplying a gas such as a source gas or a purge gas is connected to the region of the film forming unit 302 on the bottom surface of the vacuum chamber 301, and a film forming chamber exhaust mechanism 310 is connected via a pipe 309. Yes. Note that a substrate mounting table 321 having a heating mechanism is disposed on the bottom surface of the vacuum chamber 301 inside the film forming unit 302.

  The film forming unit 302 is pressed against the bottom surface of the vacuum chamber 301 by its own weight, and forms a film forming chamber formed of a sealed space inside. Therefore, when a force that pushes the film forming unit 302 upward is applied beyond the weight of the film forming unit 302, the lower surface of the film forming unit 302 is separated from the bottom surface of the vacuum chamber 301. As a result, the film forming chamber is partially opened inside the vacuum chamber 301. As a result, by using the apparatus shown in FIG. 3, as in the apparatus shown in FIGS. High-speed purge can be performed.

It is a block diagram including the typical cross section which shows the structural example of the atomic layer film-forming apparatus in embodiment of this invention roughly. It is a block diagram including the typical cross section which shows the structural example of the atomic layer film-forming apparatus in embodiment of this invention roughly. It is a block diagram including the typical cross section which shows schematically the structural example of the other atomic layer film-forming apparatus in embodiment of this invention. It is a block diagram which shows the structural example of the conventional atomic layer film-forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Vacuum chamber, 102 ... Film-forming part, 103 ... Pipe, 104 ... Exhaust mechanism, 105 ... Upper cover, 106 ... Elastic member, 107 ... Support part, 108 ... Gas supply mechanism, 109 ... Pipe, 110 ... Exhaust film-forming chamber Mechanism, 121... Substrate mounting table.

Claims (3)

A vacuum chamber with a sealable internal space;
A film forming unit disposed inside the vacuum chamber and having an opening;
A first exhaust mechanism communicating with the first region of the vacuum chamber via a first pipe;
A second exhaust mechanism communicating with the second region of the vacuum chamber via a second pipe;
A gas supply mechanism for supplying a predetermined gas into the vacuum chamber;
The second region is outside the film forming chamber sealed by the film forming unit and a portion of the first region of the vacuum chamber, and is inside the vacuum chamber,
The film forming unit is pressed against the inner wall of the vacuum chamber with a pressing force of a predetermined size so that the opening includes the first region,
A sealed film forming chamber is formed by the film forming unit and a portion of the first region of the vacuum chamber,
The atomic layer deposition apparatus, wherein the gas supply mechanism supplies gas into the deposition chamber through the first region of the vacuum chamber. The atomic layer deposition apparatus according to claim 1,
The vacuum chamber has a flat top lid,
An elastic member that supports the film forming unit to be pressed against the upper lid in the vacuum chamber;
The first region is disposed on the upper lid;
The atomic layer deposition apparatus, wherein the deposition unit is pressed against the inner wall of the upper lid by the elastic force of the elastic member. The atomic layer deposition apparatus according to claim 1,
The first region is disposed on a bottom surface of the vacuum chamber;
The atomic layer deposition apparatus, wherein the deposition unit is pressed against the bottom surface of the vacuum chamber by the weight of the deposition unit so that the opening includes the first region.

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